1. The Field of the Invention
The present invention relates to systems, methods, and apparatus for compressing or mounting a closure element for insertion within a medical delivery device.
2. Background and Relevant Art
Catheterization and interventional procedures, such as angioplasty or stenting, are generally performed by inserting a hollow needle through a patient's skin and tissue into the vascular system. A guidewire may be advanced through the needle and into the patient's blood vessel accessed by the needle. The needle is then removed, enabling an introducer sheath to be advanced over the guidewire into the vessel, e.g., in conjunction with, or subsequent to, a dilator. A catheter—or other similar device—may then be advanced through a lumen of the introducer sheath, and over the guidewire, into a position for performing a medical procedure. Thus, the introducer sheath may facilitate introducing various devices into the vessel, while minimizing trauma to the vessel wall, and/or minimizing blood loss during a procedure.
Upon completing the procedure, the operator will remove the devices and introducer sheath, leaving a puncture site in the vessel wall. The operator, such as a nurse or physician, may then apply external pressure to the puncture site until clotting and wound sealing occur. Unfortunately, this may be time consuming for both the patient and the operator, and hence expensive. For example, the procedure may require as much as an hour of a physician's or nurse's time. Furthermore, the patient will usually need to remain bedridden for a substantial period of time after clotting to ensure closure of the wound. This procedure can be uncomfortable for the patient, and generally requires that the patient remain immobilized in the operating room, catheter lab, or holding area. In addition, a risk of hematoma exists from bleeding before hemostasis occurs.
Recent apparatus developed to aid hemostasis of the puncture site include devices configured to insert a flexible closure element about a puncture site, directly on the tissue. One such flexible closure element comprises a clip made of one or more memory materials or alloys, such as NITINOL (nickel titanium alloy) wire. In operation, a user, such as nurse or physician operator, handles a delivery device to deposit the closure element directly on the tissue, where the clip surrounds the puncture site. When the user releases the closure device, the clip (i.e., closure element) releases directly onto the tissue, and relaxes into a closed conformation. The clip also latches onto the tissue surrounding the puncture site, and squeezes the puncture site together. Accordingly, and due to its relative ease of use as well as reliability, a closure element—and corresponding delivery device—such as this can provide a number of advantages over conventional suturing mechanisms.
Mounting the closure element to the delivery device, however, can be difficult. For example, a conventional closure element, or clip, comprises a flexible, circular element that can be folded into a substantially cylindrical, tensioned state. The closure element can also be threaded over a cylindrical carrier tube, which is at least partially flared at the delivery end. An at least partially-hollow pusher tube may then be inserted over the carrier tube, and positioned adjacent the tensioned closure element that is in a tensioned, cylindrical configuration. In addition, the pusher tube generally includes a plurality of flanges or fingers that are at least partially flared away from the major vertical axis defined by the carrier tube, where the flaring aids contact with the closure element. A technician then inserts an assembly of the carrier tube, closure element, and pusher tube, in turn, within a garage tube that is configured with sufficient diameter to receive each of the items together. The pusher tube flanges and the closure element can be sufficiently compressed or tensioned toward the major axis defined by the carrier tube.
Compressing the pusher tube flanges and compressed/tensioned closure element against the major axis of the carrier tube, however, can be difficult, and time consuming. Conventional methods for tensioning this assembly of parts generally include hand assembly and subsequent hand compression thereof, and then manually pushing the components into the garage tube.